Japanese Americans are a group that has a sizable population of people who have lived their entire lives in the US. If you think that they would be more likely to behave similarly to people who have spent their whole lives in Japan, the burden of proof is on you, because that certainly is not a mainstream view.

1) Confusion between Japanese in America and Japanese-Americans

2) "More likely to behave similarly" is a considerably wider net than just crime rates

3) I think the mainstream view is that East Asians of all stripes commit considerably less crime than average. It's certainly true of violent crime, which is something I've looked in to.

These are Americans, not Japanese.

That is an interesting way to slice it.